On Sat, March 24, 2018 7:58 pm, Nico Huber wrote:
On 24.03.2018 13:49, awokd via flashrom wrote:
I haven't fully followed the power rails in the
what you witnessed sounds much like you also power the PCH and maybe the EC
too. The overall board layout regarding the SPI flash looks astonishing. I
wonder why it works at all ;)
"Astonishing" is not very promising sounding. :)
You might already know the
`laptop=force_I_want_a_brick` option for
internal flashing. This option was introduced because of severe trouble
with *less* complex situations. It looks like Wistron already placed two
masters on the SPI bus (it should only be one) and your programmer is the
I missed that completely.
If I understand things correctly, the flash chip is
shared as much as
possible (understandable for such a cheap machine).
I'm prepared to sacrifice this machine on the altar of knowledge, although
I am going to miss the nice keyboard.
1. the EC stores its
firmware in it. 2. the ME loads some of its firmware directly over SPI. 3.
the BIOS is loaded over LPC through the EC (that's the I_want_ a_brick
scenario). My vague guess is that it only works because the EC can somehow
predict when the ME is going to access the SPI flash (e.g. within some ms
after enabling certain power rails).
I see three solutions here:
1. Desolder the flash chip completely. If you just want to flash once,
solder it back afterwards. Otherwise, add some isolation circuit.
2. Replace R6010 and R6011 with diodes. Make sure to remove all bat-
teries and AC, and power the flash chip directly during programming.
3. Cut the VCC pin of the flash chip, solder it together again later
people are doing that).
My personal choice would be 2., I would never try 3. (chances are too
high that you hurt the pad below the VCC pin).
Was hoping to avoid soldering (anything finer than 12 gauge makes me
nervous) but sounds like no choice. I don't follow how
desoldering/soldering 8 or 2 legs is safer than 1 but I'm sure there's
something on Youtube explaining. Maybe it's easier than I think and I just
need to practice. If I can't get it, you might see my own contribution of
a special method of removing ME by judicious application of 220V AC.
Thanks for taking a look!